What is a homologous series? Explain with an example.

AcademicChemistryNCERTClass 10

Homologous series is a group of organic compounds having similar structures and similar chemical properties in which the successive compounds differ by CHgroup.

Example: All the alkanes have similar structures with single covalent bonds and show similar chemical properties, so they can be grouped together in the form of a homologous series.

[Extra information: Certain compounds contain only carbon and hydrogen. Hence, these organic compounds are called hydrocarbons.The hydrocarbons which are members of the same homologous series are:

Alkanes: C3H8, C4H10

Alkenes: C5H10, C8H16

Alkynes: C6H10, C7H12

Characteristics of a homologous series are given below:
(i) All the members of the homologous series can be represented by the same general formula.
(ii) Any two adjacent homologues differ by 1 carbon atom and 2 hydrogen atoms in their molecular formulae.
(iii) The difference in the molecular masses of any two adjacent homologues is 14 u.]
Updated on 10-Oct-2022 12:47:19